Statistica Sinica 12(2002), 905-916

QUASI-ORTHOGONAL ARRAYS AND OPTIMAL

FRACTIONAL FACTORIAL PLANS

Kashinath Chatterjee$^*$, Ashish Das and Aloke Dey

$^*$Asutosh College, Calcutta and Indian Statistical Institute, New Delhi

Abstract: Generalizing orthogonal arrays, a new class of arrays called quasi- orthogonal arrays, are introduced and it is shown that fractional factorial plans represented by these universally optimal under a wide class of models. Some methods of construction of quasi-orthogonal arrays are also described.

Key words and phrases: Fractional factorial plan, quasi-orthogonal array, universal optimality.